Phase I: The overall objective of this project is to develop an inexpensive test of olfactory function for use in the clinical assessment of the sense of smell. The test will be based upon an olfactometer employing state-of the-art technology, specifically, Micro-Electro-Mechanical Systems (MEMS), i.e., microvalves. (Microvalves are produced using techniques analogous to those used in manufacturing integrated circuits, resulting in a dense array of valves in a very small area.) The incorporation of MEMS microvalves into a clinical test of olfactory function is a unique approach in solving the complex problems associated with generating and controlling the large number of different odor stimuli required for such a test. This device will be able to administer, score, and record the results in response to commands received via the World Wide Web (WWW). The test, in reality, becomes a Web based application available world wide, once the MEMS-based olfactometer has been attached to a computer connected to the WWW. In this Phase I application, the use of microvalves as the basis for a clinical olfactometer will be investigated. Three Specific Aims are proposed: 1) to evaluate the feasibility of using MEMS microvalves as a means for generating odor stimuli in a clinical olfactometer; 2) to develop an odorant containment system compatible with the MEMS microvalves; and 3) to characterize and duplicate the odorant stimuli used in the University of Pennsylvania Smell Identification Test (UPSIT), a widely used and well standardized test of olfactory function, in order to develop a comparable set of stimuli for the MEMS-based olfactometer. A clinical test of olfaction incorporating the MEMS olfactometer will be more economical than tests currently available, will permit self-administration, and will allow collection of all relevant information directly into a digital format (computer file). Successful development of this clinical test of olfactory function will permit routine examination of the sense of smell in the general population at a minimal cost. The ability to accomplish this is becoming even more important as the population grows older and olfactory function is diminished or lost, due to natural aging processes, or the onset of numerous neurodegenerative disease states such as Alzheimer's and Parkinson's disease.